Apparatus for reclaiming spent foundry sand



Dec. 30, 1947. A. c. CHRISTENSEN 2,433,738

' APPARATUS FOR RECLAIMING SPENT FOUNDRY SAND Filed April 6, 1944 s Sheets-Sheet 1 .ENDE

Dec. 30; 1947.

A. C. CHRISTENSEN APPARATUS FOR RECLAIMING SPENT FOUNDRY SAND Filed April 6, 1944 3 Sheets-Sheet 2 WM 1 W DeQ 1947- A. 9. CHRISTENSEN 2,433,738

APPARATUS FOR RECELAIMING SPENT FOUNDRY SAND Filed April 6, 1944 3 Sheets-Sheet 3 Patented Dec- 30, 1947 APPARATUS FOR RECLAIMIN G SPENT FOUNDRY SAND Alfred C. Christensen, Chicago, Ill., assignor to Herbert 8. Simpson, Evanston, Ill.

Application April 6, 1944, Serial No. 529,770

7 Claims. 1

vThe present invention disclosed and claimed herein pertains to a method of and apparatus for more efficiently reclaiming spent and inert materials such as used foundry sand and the like, by batch feeding of the material into the top of the apparatus and subjecting the material in batches to successive preheating, burning and cooling treatments as the batches are fed downwardly by gravity through superimposed levels whereby the material being treated is economically reclaimed for reconditioning and reuse.

In establishments using granular materials, such as a foundry using mold and core sand, said sand usually consists of silica grains combined with bonding agents tempered with sufllcient moisture to develop the strength of the binders and to render the sand moldable. After such sand has been used for making molds, cores, and the like, it becomes spent or inert and due to the heat to which the sand is subjected, it becomes coated with unburned bonding material and carbon to such an extent that the sand is no longer fit for further use and must consequently be dis carded. This constitutes a considerable waste and the additional expenditures necessary to purchase new clean sand are such that it is highly desirable to reclaim the original sand and then recondition the same for further use.

It is an object of this invention to provide an improved method and machine for reclaiming inert and spent foundry sand and similar granular materials, which method and machine is economical, clean and effective.

It is also an object of this invention to provide an improved method and machine for reclaiming spent and inert used granular materials by conducting the materials downwardly through a vertical path or course and subjecting the materials to preheating and agitating treatments, burning and rabbling treatmentsand then subjecting the materials to mixing, mulling and aerating treatments and simultaneously removing the fines therefrom to produce a cleaned reclaimed material ready for reconditioning and reuse.

A further object of the invention is to provide an apparatus consisting of superimposed units for reclaiming and reconditioning previously bonded granular materials such as foundry sand and the like, by subjecting a plurality of batches of the material in difierent superimposed units of the apparatus to selectively controlled timed treatments consisting of first agitating and preheating the material, then subjecting the same to multaneously operable through a common drive sufilcient heat to burn oil and remove the bonding and carbonaceous coatings from the material grains and then aerating and cooling the material and simultaneously dry scrubbing the same and removing the fines therefrom to produce a resultant cleaned and cooled material suitable for rebonding, retempering and reuse.

and aerating mechanism whereby a plurality of batches at difierent levels may be subjected to agitating and preheating treatments, then to burning and oxidation treatments, and then to aerating, cooling, mixing, mulling and fine removing treatments during the successive travel of the respective batches downwardly through the machine to be batch discharged in a cleaned condition ready for retempering and rebonding to recondition the reclaimed batches for reuse.

It is furthermore an object of this invention to provide an improved method and apparatus for reclaiming inert foundry sand and the like by batch feeding the material downwardly through successive areas and subjecting a batch during its passage through the machine to agitating, buming and oxidating, and to mixing and mulling treatments in the presence of air currents admitted around and through a common drive to serve as a cooling medium, in a cooling area, as an oxygen supply in the burning area, and as a preheating medium in the material receiving area whereby the material batch is successively treated in the respective areas and is finally subjected to a fine removing suction action before being batch discharged in a cooled and cleaned condition read to be stored or subjected to retempering and rebonding treatments to recondition the material for further use.

Another object of the invention is to provide a sand reclaiming system wherein a batch of material is' agitated and preheated before being batch fed into a confined area heated to a selected temperature for burning ofi spent bonding agents and carbonaceous coatings while the material is being mixed and air treated before being batch fed into a confined area to be mulled, mixed and air cooled while the fines and dust are suctioned from the cleaned cooled batch of material prior to discharge for storage or reconditioning treatments.

Another feature of the invention is to provide a vertical type of machine adapted to be batch fed from the top, permitting the batches to be advanced through a series of consecutive superimposed treating areas, whereby the various batches may be subjected to different treatments .in the respective areas by different sets of mechanisms operated by a common driving means, with one of said areas being subjected to high temperatures to cause cleaning by burning and oxidation in the presence of air currents with a utilization of the heated air and hot gases as a means for preheating a batch of material in a asssnss 3 higher area before the material is permitted to drop by gravity into the high temperature area.

An important object of the invention is to provide an improved method for reclaiming spent foundry sand and the like, said method including controlled batch feeding with the aid of gravity, said method also including the consecutive subjection of the batches to agitating and preheating treatments, to burning and oxidation treatments in the presence of circulating air currents, and then to cooling, mixing, mulling and dust and fine removing treatments in a confined area in the presence of cool air circulating currents which are subsequently utilized for circulation through the burning and oxidating area and then through the preheating area in a direction opposite to the movement of the material, batches through the various material reclaiming stages of the method.

Other objects and features of this invention will be apparent from the disclosures in the specification and the accompanying drawings:

On the drawings:

Figure 1 is an elevational and sectional view of an apparatus or machine constructed in accordance with the principles of this invention and capable of expeditiously and economically carrying out the methods of reclaiming spent granular materials such as foundry sand and the like.

Figure 2 is an enlarged fragmentary vertical sectional view, with parts shown in elevation, and taken through the common driving mechanism and the air supply and circulating means for the three superimposed material feeding units of the improved apparatus.

Figure 3 is a horizontal sectional view taken on line I[II1I of Figure 1 through the mixing and preheating top unit of the apparatus.

Figure4 is a transverse sectional view taken on line IV- IV of Figure 1 looking downwardly in the burning and oxidation or intermediate unit of the apparatus.

Figure 5 is an enlarged vertical detail sectional view taken on line V-V of Figure 1 and transversely across one arm of the material mixing and air distributing rabble mechanism within the confined area of the burning and oxidizing interme diate unit.

Figure 6 is a transverse sectional view taken on line VI-VI of Figure 1 and looking downwardly into the cooling, mixing and mulling unit of the apparatus.

Figure 7 is a transverse sectional view taken on line VII-VII of Figure 1 through the lower part of the upper preheating unit to show the diametrically disposed material discharge control doors or plates in closed position over the diametrical discharge slot in the bottom of the upper unit and also indicating the dotted line open positions of the discharge doors.

Figure 8 is a transverse detail section taken on line VIII-V111 of Figure 1 looking upwardly in the intermediate high temperature unit of the apparatus to show the air supply openings in the bottom of the rabble arms of the rotatable rabble blade mechanism.

Figure 9 is an enlarged fragmentary vertical detail section taken on the line IX-IX of Figure 1 through the preheating unit rabble blade mechanism and showing the registering dischar e slots or openings between the top unit and the intermediate unit of the machine.

As shown on the drawings:

The improved method of cleaning and reclaiming'spent or inert granular materials such as foundry sand and the like is adapted to be accomplished by means of a vertical machine assembly or system of the type illustrated in Figure 1 and which includes a superimposed grouping of various batch treating units permitting batch feeding of the material with the aid of gravity from one unit into the next lower unit. The improved machine assembly includes a common drive mechanism combined with an air supply and circulating means whereby a plurality of batches in different units may be simultaneously treated and subjected tothe action of air currents while being treated or actuated by rabble mechanisms in the two upper units, and while the batch in the lowermost unit is being cooled and subjected to mulling and mixing treatments while the fines and dust are removed prior to the discharge of a cleaned cooled batch ready for storage or reconditioning for reuse.

As clearly illustrated in Figure l, the improved machine assembly is preferably disposed within a building, which has been omitted except for the roof section I. Disposed within the building is a supporting framework Idncluding a vertical frame 8 upon which a controlled material bucket type feeder is supported for batch feeding the material to be reclaimed by discharging the batches, in timed order, into the upper end of the machine.

The batch type bucket feeder comprising a batch bucket 4 which when in its normal position, as indicated in full lines in Figure 1, is positioned adjacent a loading platform II from which the spent or inert sand or other material, which is to be reclaimed, is adapted to be deposited into the bucket when in a receiving position. The batch feed bucket 4 is adapted to be alternatel raised and lowered by means of a cable 8 adapted to be wound and unwound by means of a drum mounted on the upper portion of the machine framework and operable by means of a motor I acting through a speed reducer drive 8. The operation of the bucket 4 is accomplished by means of a reversing switch 9 supported in a convenient position on the feeder frame 3. The switch 8 is connected with a combination start, stop and reverse push button control It also mounted on the feeder frame 3. The batch feed bucket 4 is provided with upper and lower rollers II which track in guide tracks l2 and auxiliary guide tracks 13 supported on the frame 3. The auxiliary guide tracks B are located near the upper portion of the frame 3 and are adap ed to serve as guides for the lower rollers ll of the loading bucket 4, when the upper rollers reach the upper closed ends of the main guide tracks I! to cause the loading bucket at the upper limit of its movement to be upset or reversed to tilt the same to cause discharge of a batch of the material into a receiving hopper l4. The material receiving hopper I4 is provided with a discharge door I 5 the operation of which is controlled by means of an air operated plunger rod mechanism It.

A batch of spent sand or material, which is to be reclaimed. is adapted to be discharged from the feed hopper l4 into an end opening I! provided in a roof or top. l8, which forms the top of the material reclaiming machine or apparatus. The machine is of the vertical type and has the various material treating units thereof mounted in siugerimposed relationship upon the framewor The material reclaiming machine or apparatus consists of three superimposed units namely a top eans or material preheating unit A. an intermediate or burning unit B upon which the preheating unit A is supported, and a lowercooling, stirring and mulling unit C upon which the middle or burning unit is supported. I

The top or preheating unit A includes the roof or top II which is constructed of fire bricks or other suitable refractory material and in addition to the entrance opening I1, is provided with a central opening I! and an outlet or escape opening 28. The top or preheating unit A of the machine in addition to the refractory top l8 includes a refractory cylindrical body or lining 2| which is disposed within a cylindrical metal housing 22. The preheating unit also includes a refractory bottom 28 which is formed with a diametric discharge slot or opening 24 through which a batch of material after being preheated and treated in the preheating unit A is adapted to be discharged downwardly with the aid of gravity through a diametric material inlet slot or opening 26 formed in, a heat insulation top wall 28 disposed directly beneath the refractory bottom or floor 28 of the top unit A.

The middle of the refractory bottom or floor 23 of the top unit A and the middle of the insulation top wall 28 of the burning unit B are each provided with a central opening. A door supporting and air circulating sleeve or hub 21 is rotatabiy engaged through the central openings to form a communication between the interiors of the top and middle units A and B. Rigidly secured to or integrally formed on the sleeve or hub 21 are segment-shaped shutters or blades 28 which form a control door over the registering slots 24 and 25 to govern the discharge of a batch of material from the upper preheating chamber 28 of the unit A into the burning chamber 88 of the intermediate unit 13. The control door, formed by the diametric blades 28, is adapted to be shifted into open and closed positions with respect to the discharge slot 24, by means of a radially projecting arm 8| which projects outwardly through a slot 82 formed in'the lower portion of the top unit refractory body wall or lining 2| and the outer housing wall 22. Pivotally connected to the outer end of the dooroperating arm II is a piston rod 88 which slidabiy projects into an air controlled cylinder 84 supported in place by means of a bracket 88 secured to the housing 22 of the .top or preheating unit A.

A batch of material delivered from the hopper l4 through the entrance opening II, when the hopper door Ills opened, is discharged into the chamber 29 of the preheating unit A and is adapted to be agitated or stirred up by means of a plurality of rabble blades 88 which are mounted in spaced relation on a pair of radially opposite or diametric rabble arms 21. The inner ends of the two rabble arms 81 are rigidly secured in a collar 88 which in turn is rigidly fastened around a centrally disposed upper hollow driving and air circulating shaft section 88 which forms a part of a main operating shaft centrally disposed in and common to all three of the superimosed units A, B and C as clearly illustrated in Figure 1.

The main air supply and driving shaft is formed in sections and has the lower end thereof supported in a lower bearing 40. The main shaft projects upwardly and centrally through the three treating units A, B and C and has the upper shaft section 88 projecting out through the central opening l8 of the top unit A. The upper end of the shaft section 88 engages in an upper bearbers of the ing 4! mounted on upper horizontal frame memframework 2. The upper end of the air circulating and operating shaft section 89 projects upwardly into an elbow pipe 42 which connects up with one side of a collector 43. The collector 48 is supported on the framework 2 and has the lower end thereofdevised to form a hood which is disposed over the outlet or escape opening 20 in the roof or top iii of the top unit A. The upper end of the collector 43 projects upwardly through the roof I of the building to permit escape of the air passing upwardly through the shaft section 89 and the heated air from the chamber 29 of the top unit A. Any dust or fines from the top chamber 29 are carried off into the collector 48 by the escaping heated air leaving the top unit A. Keyed or otherwise rigidly secured on the lower section of the main shaft above the lower bearing 48, is a large driven gear 44 which is in mesh with and receives a drive from a small driving gear 45. The gear 45 is secured on the shaft of a driving motor 46 which is mounted on horizontal frame members near the bottom of the framework 2 as shown in Figure 1.

A batch of material after having been agitated 'and stirred by the rabble blades 36 in the upper preheating unit A and having been sufliciently preheated, is adapted to be batch discharged from the top chamber 29 by opening the door blades 28 allowing the partly treated and preheated batch of material to drop downwardly by the aid of gravity through the registering openings 24 and 25 into the burning chamber 30 of the intermediate unit B of the machine. The burning or middle unit B comprises a cylindrical metal housing 41 which forms a casing for enclosing an inner housing consisting of the insulation top wall 26, a cylindrical insulation wall 48 adjacent the inner surface of the metal housing 42 and surrounding a refractory inner wallor lining 49. The burning unit B also includes a refractory bottom or floor 50 disposed about an insulation bottom ii. The inner wall 49 and the inner bottom floor 50 are constructed of refractory material such as fire brick or the like. The refractory walls are surrounded by the top wall 26. the side wall 48 and the floor bottom 5| all of which are constructed of an insulation material whereby the high temperatures required for the treatment of the material, are adapted to be maintained in the burning chamber 30 of the intermediate unit 13.

The hollow main shaft also includes an intermediate hollow shaft section 52 whichis disposed axially in the intermediate unit B and is provided with a top flange which is rigidly secured to a bottom flange of the top or upper shaft section 89. Integrally formed on the intermediate shaft section 52, within the chamber -30, are a pair of diagonally opposite supporting arms 53 the outer end of which are provided with flanges. Rigidly secured to the flanges on the ends of the supporting arms 53 are a pair of radially disposed diametric hollow rabble arms 54 the bottom wall of each of which is provided with a plurality of spaced diagonally positioned air distributing slots or apertures 55 clearly illustrated in Fig- -ure 8.. Rigidly secured or integrally formed on the bottom of each of the hollow rabble arms 54 are a plurality of' spaced diagonally positioned rabble blades 56. Rotation-of the main shaft causes rotation of the rabble blade carrying air supply arms 54 to cause the batch of preheated material, received from the upper preheating unit A, to be mixed and agitated in the chamber 30 of the intermediate burning unit B. The slots or apertures 55 in the arms 54 are adapted to discharge air at ordinary temperature into the chamber 30 to supply a'sumcient amount of oxygen whereby oxidation may take place within the chamber 30 during the treating of the particles of the material being treated.

For the purpose of subjecting the material in the chamber 30 of the intermediate unit B to substantially high temperatures ranging from approximately 900 to 1200 F. a gas or oil burner 51 is mounted on the exterior of the intermediate housing 47 and includes a flame throwing nozzle 68 which projects through registering openings in the housing 41 and in the inner walls 48 and 49 whereby heating flames may be directed into the chamber 30 to produce the required temperatures, thus the granular particles of the batch of material being dry scoured in the chamber 30 are adapted to be further cleaned by having the coatings of the old bonding materials and foreign matter burned off of the grains by an oxidation treatment to complete the cleaning of the batch of material.

The superimposed bottoms 50 and of the intermediate unit B are provided with diametric registering discharge slots or openings 59 which register with a third diametrical discharge slot or opening 59 formed in a top wall 60 formed of metal or other suitable material. The top wall 60 forms the top of the lower cooling and mulliing unit C of the machine. The two superimposed bottoms 50, 5| and the top wall 60 are provided with registering central openings intersected by the discharge slots 59. Projecting through the central openings of the bottoms 50 and El, and the top wall 60 is an air circulating collar or sleeve 6| through which the lower arm of the intermediate driven shaft section 52 projects to extend into a cooling chamber 82 of the lower unit C. To retain the batch of ma terial within the burning chamber 30 a diametric control door 63 is provided within the intermediate unit B and said door consists of a pair of diametrically opposite or radial shutters or blades having their inner ends thereof rigidly secured to a collar which is rotatably engaged on the air circulating sleeve or collar 6| to permit the door to be rotated to cause opening of the discharge opening in the bottom of the intermediate unit B to permit a cleaned hot batch of material from the chamber 30 to be dropped by the aid of gravity into a mixing and mulling chamber 64 provided within the lower cooling chamber 62 of the bottom unit C. .A radially directed door operating arm 65 is rigidly connected to the door 63 and projects out through a slot in the walls of the intermediate unit 3 to permit the outer end thereof to be pivotally connected to a piston rod 66 which forms apart of an air control cylinder 61 mounted on a bracket 68 secured to the exterior of the cylindrical metal housing 41 of the middle unit.

The batch of material after being hot treated or cleaned by the burning process within the chamber 30 is permitted to be discharged through the registering discharge openings 59 in the bottom of the unit B into the lower or cooling unit C. The lower unit 0 is a combination cooling,-

mixing and mulling unit including the metal top wall 60 which is supported on a metal outer cylindrical casing or housing 6!! closed by means of a bottom 10 which is rigidly supported by legs or standards II which form a part of the framework of the machine. Securely mounted within being cleaned by being subjected to the rabbling and oxidation treatments. The inner cylindrical casing 12 is provided with a replaceable wear plate I3 which serves as the bottom of the inner casing 12 and rests upon the top surface of the bottom 10 of the lower unit C, as clearly illustrated in Figure 1.

The common hollow main driven shaft for the machine in addition to the upper section 89 and the intermediate section 52, consists of a slightly enlarged lower tubular shaft section 14 the lower end of which is engaged in the bearing 40 and has the driven gear 44 secured thereon. The upper end of the lower shaft section 14 projects upwardly through an opening in the bottom of the lower cooling unit C and has the lower end of the shaft section 52 rigidly secured therein. The lower shaft section 14 is provided with a series of air intakes or apertures II.

Air is supplied to the lower apertured shaft section 14 from an air supply elbow 18. The vertical portion of the air supply elbow 16 projects upwardly through an opening in the bottom of the lower cooling unit C and is spaced circumferentially around the lower driven shaft.

section 14 as clearly illustrated in Figures 1 and 2 to permit air to be admitted into the lower mulling and mixing chamber 64 of the lower unit C as well as into the air receiving apertures 15 of the common driven shaft of the machine. The lower shaft section 14 projects axially upwardly into the elbow 18 so that the apertures 15 of the lower shaft section are disposed within the elbow. The horizontal portion of the air supply elbow 18 has the outer end thereof rigidly connected to the outlet of an air blower 11 operated by means of a belt I8 from a driving motor 19 mounted beneath the lower cooling unit C on lower members of the machine framework 2.

It will thus be noted that cool air from the blower I1 is adapted to enter the apertures 15 in the lower section of the driving shaft permitting the air to pass upwardly through the shaft to the various superimposed material treating units and actin to serve as a cooling medium for the upper shaft bearing 4! before the air thereof. Air from the blower TI also passes upwardly through the elbow l6 and enters the lower inner chamber 64 and the outerchamber 62 of the lowermost cooling unit C from which the air is permitted to pass upwardly through the collar or sleeve 6| into the burning chamber 30 of the intermediate or burning unit B to be heated to high temperatures by the flames from the burner 51.

The highly heated air from the chamber 30 is then permitted to pass upwardly through the sleeve or collar 21 into the upper chamber 29 of the top unit A to serve as a means for preheating the material as it is being agitated and stirred to dry scour the same by the action of the rabble blades 36 when the rabble blade carrying arms 31 are rotated by the action of the rotating common driven and air circulating shaft. The preheated aasaraa air from the preheating chamber 28 is permitted to escape through the outlet opening 28 in the roof or top l8 of the top unit and is permitted to enter through the lower end of the collector 48 carrying with it any light dust or fines resulting from the treatment of the material batch in the chamber 28.

Air passing upwardly through the hollow main driven shaft is also adapted to pass transversely through the arms 58 into the hollow rabble arms 54 to be discharged or fed downwardly through the rabble arm outlet or air feed slots or apertures 55 to enter into the burning chamber 38 of the intermediate unit B to be discharged against the material while being rabbled. This arrangement permits suflicient oxygen to be supplied to the burning chamber to coact with the combustion gases from the heater to cause oxidation and a cleaning off of the old bonding and foreign matter coatings from the grains of the batch of material being agitated and mixed by the rabble blades 55 when the rabble arms 54 are rotated with the rotation of the hollow driven shaft.

For the purpose of treating a clean batch of hot material received from the intermediate heating unit B, the lower unit C is equipped with a mulling and mixing mechanism consisting of a supporting collar or head 88 which is rigidly secured around the upper end of the lower shaft section I4 within the inner housing 12. Pivotally supported on opposite sides of the collar or head 88 are a pair of radially directed muller supporting arms 8| and 82 with the arm 8| being shorter than the arm 82. Rotatably mounted on the outer ends of the arms 8| and 82 are mullers 83. Also rigidly secured to the collar 88 is an arm 84 on the lower end of a vertical extension of which a scraping blade 85 is supported. The scraping blade 85 is positioned to have the outer end thereof engaged adjacent the inner face of the inner casing wall I2 to serve as a scraper while the lower end of the scraper 85 is adapted to pass over the t p surface of the replaceable liner wear plate 13. Also rigidly secured to the collar 88 is a shorter arm 86 the outer end of which is directed downwardly or isprovided with a vertical extension on the lower end of which a plow blade 81 is secured to pass over the wear plate 13 for plowing the material being treated and for moving the material into the path of travel of the mullers 83.

The batch of material, having been deposited in the inner chamber 84 of the inner casing 12 of the lower unit C, is adapted with the rotation of the maindriven shaft to be mixed and mulled in the presence of air currents circulating and passing through the inner chamber 64 and then passing upwardly through the collar or sleeve 6| into the burning chamber 38 of the intermediate unit B. While the material is being mixed, mulled and cooled in the chamber 54 of the lower cooling unit C, part of the air entering thechamber 64 of the lower cooling unit C passes over the top of the inner housing wall 12 into the space between the circular wall 12 and the outer casing wall 68 carrying with it any fines and dust still remaining in the material while undergoing its flnal treatment so that the fines and dust may be carried out through an outlet flue 88 having one end thereof connected around an outlet opening in the lower casing 58 while the other end thereof is connected to project into one side of a fine and dust collector 89 in which the fines and dust are permitted to settle and be drawn oil through the lower hopper end 88 formed on the l0 bottom end of the collector 89 while the air is permitted to escape outwardly through the top of the collector through a discharge stack or flue 8| which projects upwardly through the roof I of the building in which the machine is installed.

In order to prevent the hot material discharged from the burning chamber 38 into .the cooling chamber 54 of the muller unit C from entering the vertical section or arm of the air inlet elbow 18 within said chamber 64, a material deflecting shield 92 is mounted around the lower shaft section 14 above the open upper end of the vertical part of the air inlet elbow I6 as clearly illustrated in Figure 2.

After the material in the lower cooling unit 0 has beenmixed, mulled and cooled for a timed period the duration of which may be governed by the attendantof the machine, the attendant merely operates an air control which governs the operation of the air control cylinder 84 carried by a bracket supported on the machine framework. The air control cylinder 84 and the other air control cylinders of the machine have air intake and outlet pipes 83 connected therewith. An air operated plunger rod 86 projects from the cylinder 84 and has the outer end thereof pivotally connected to a door operating lever or handle 81 which is integrally formed at an angle at the outer tapered end of a' discharge door 88. The discharge door 88 is pivotally supported on a suitable bracket exterior of the outer housing or casing 68, of the lower unit C, and has the main portion of the door disposed in a suitable slot in the side of the lower unitC so that normally the door 88 is engaged in the full line position illustrated in Figure 6 to cover a discharge opening 88 provided in the bottom or floor members 13 and ill of said lowermost unit.

The discharge opening 88 registers with the upper end of a material discharge chute Hill which projects downwardly beneath the machine into a position to permit a material receiving cart or wheelbarrow I 8| to be moved into position beneath the discharge end of the chute to receive the batch of cleaned dry and cooled reclaimed sand or other material to permit the batch to be carted away for storage until needed or to a station containing suitable apparatus to permit the cleaned, reclaimed cool material to be retempered and rebonded to completely recondition the same so that the reclaimed material may again be used for making foundry molds, cores and the like.

The apparatus'or machine assembly whereby the improved method of reclaiming foundry sand and similar materials is adapted to be accomplished, is illustrated in Figure 1 and consists of a plurality of superimposed treating units each of which is equipped with material actuating mechanisms all of which are adapted to be simultaneously operated from a common combination drive and air circulating shaft. The machine permits a series of batch treatments to be conducted simultaneously in the various'units in which the respective batches may be subjected to the successive timed treatments of the improved reclaiming method or process. v v

The improved method or process adapted to be practiced by means of the improved machine assembly or apparatus such as illustrated in Figure I 1, consists of batch feeding the material to be reclaimed, such as previously used foundry sand obtained from old foundry molds or cores which are first crushed and then treated by any standard means whereby the metallic particles and the excessive dust and lines are first removed. The resultant used or spent granular foundry sand or similar material is then delivered in batches through the top of the machine into the uppermost unit where the material is subjected to a rabble agitating treatment while being subjected 'to hot air currents to preheat the material batch for a manually controlled period of time after which the preheated batch is discharged by gravity into a lower highly heated area of zone which supplies hot air to the upper preheated area and simultaneously subjects the material batch in the second area to high temperatures in the presence of air currents to cause the batch to have the coatings of old bonding materials and foreign matter burned therefrom by oxidation assisted by the projection of cool air drafts from a rabbling means which dry scours the batch leaving the same in a cleaned hot condition ready to be discharged. The hot cleaned batch after a -time' treatment is next discharged into a cooling area where the batch is subjectedto mixing, plowing v and mulling actions in the presence of moving cool air currents to cause cooling of the cleaned material by the air currents which partially travel into the burning area while the remaining air currents are discharged for drawing off the remaining dust and fines allowing the thoroughly dry reclaimed material batch to be batch discharged for storage or for transfer to reconditioning I means wherein the batch may-be retempered with the required quantities of water and mixed with selected bonding agents to prepare the material so that it may again'be used for making foundry tendant, by a manual operation of the air pressure control mechanisms connected with the various discharge doors of the three superimposed treating units of the machine thereby permitting a treated batch to be discharged from one of the units before a new batch is admitted from another unit or from the batch supply feed hopper. The supp y of material in batches to the machine is also manually controlled by means of the push button control It connected with the reversing orcontrol switch 9 of the batch feed mechanism.

While a selected machine assembly or system has been illustrated and described for practicin the improved method or process of reclaiming spent or inert foundry sand and other similar materials, it is to be understood that the machine is one exemplification of the principles involved, and the right is accordingly reserved to make such changes in the construction and in the arrangement and combination of the unit and the parts of the system as will widen the field of utility and increase the adaptability of the system without departing from the principles of this invention. It is, therefore, not the purpose to limit sand, which includes a first unit, means for delivering a batch of spent foundry sand to said unit, a rabble mechanism in said first unit, a discharge mechanism in said first unit operable for permitting a discharge of the batch after being treated in the first unit, a second unit positioned beneath the first unit, a combination rabble and fresh air supply mechanism in said second'unit for treating a batch of the foundry sand received from the first unit and for supplying air thereto, a burner mechanism connected with the second unit for subjecting the sand while being rabbled and aerated to a temperature sufficient to produce oxidation to remove the bonding and carbonaceous coatings from the sand grains to produce a clean, hot dry sand. 9. third unit arranged beneath the second unit, scraping, plowing and mulling mechanisms in the third unit, a discharge doormechanism in the second unit for discharging a batch of the sand from the second unit for delivery into the third unit, a discharge door mechanism connected with the third unit, a combination driving and air distributing unit projecting through the first, second and third units and supporting and operating the rabble mechanisms in the first unit, the combination rabbleand air supply mechanism in the second unit and the scraping, plowing and mulling mechanisms in the third unit for simultaneously subjecting the sand batches in the three units to reclaiming treatments, and an air supply mechanism connected with the driving mechanism. and with the third unit to supply air thereto and to the first and second units, said air being heated in the second unit before entering the first unit for preheating the batch in the first unit.

v 2. An apparatus for reclaiming spent foundry sand which comprises a refractory top unit, a batch feeding mechanism for delivering a batch of foundry sand to the top unit, a rabble mech anism in the top unit, means for preheating the sand in the top unit, a refractory burning unit beneath the top unit, an'insulation housing for the refractory burning unit, a combination rabble and air supply mechanism in the burning unit,

means for heating the interior of the burning unit to subject the sand while being rabbled and treated with air to the eifect of high temperatures tending-to cause oxidation to remove the bonding and carbonaceous coatings from the sand grains to produce a hot cleaned sand, a door discharge mechanism in the top unit for delivering the batch of sand from the top unit into the second unit, a door discharge mechanism in the second unit for discharging a batch of cleaned hot sand from the second unit, a cooling unit beneath the second unit for receiving the batch of cleaned hot sand, a casing in the cooling unit circumferentially spaced from the walls of the cooling unit, scraping, plowing and mulling mechanisms in the casing within the cooling unit, a discharge door for the cooling unit casing for the discharge of material therefrom, an air circulating sleeve projecting from the second unit up into the first unit, an air circulating sleeve projecting from the cooling unit upwardly into the second unit, an

' air supply mechanism for delivering cool air into the inner casing of the cooling unit permitting some of said air to pass upwardly through said sleeves into the second unit and into the first unit, a combination drive and air circulating shaft having apertures for receiving air from said air supply means, said shaft permitting said air to pass upwardly into the combination rabble and air feed mechanism of the second unit, said combination drive and air shaft projecting upwardly through all of said units and supporting the sand treating mechanisms in the respective units to causeoperation of the same, means for operating the combination drive and air shaft mechathe cooling unit 13 nism to cause simultaneous treatments to be given to batches of the sand in the various units, an air and fines collector positioned above the top unit and connected with the upper end of the combination air and drive shaft mechanism, a

second air and fines collector, and means connecting the second collector with the cooling unit for the removal of fines from the inner casingof into said second collectorwith the escape of air current from the cooling unit into said second collector.

3. A spent granular material reclaiming apparatus comprising a refractory preheating unit,.

means for feeding a batch .of spent material vthereto, a burning unit beneath the preheating unit, said burning unit comprising a refractory inner casing and an outer insulation housing, a

cooling unit beneath the burning unit and comprising an outer housing and an inner casing, a

' hollow drive shaft projecting through all of said nected with the burning unit for heating the in- I terior of the burning unit refractory casing to temperatures sufficiently high to produce oxidation and dry cleaning of the material being treated in the burning unit, said. heated air from the burning unit continuing up into the preheating unit to cause preheating of the material therein, a collector connected with the preheating unit for receiving escaping hot air therefrom and removing dust and fines resulting from the treatment of the material in the preheating unit, means connected with the cooling unit for withdrawing fines during the cooling treatment of the material, and discharge mechanisms connected with each of the units for governing the discharge of the material therefrom into the succeeding units and from the cooling unit.

4. A spent material reclaiming apparatus including a top unit, an intermediate unit, a lower unit, said units being superimposed one upon the other and in communication with each other, means for batch feeding the material through the superimposed units, a driven shaft projecting through all of said units, means for driving the driven shaft, a rabble mechanism in the top unit supported on the driven shaft, a rabble mechanism in the intermediate unit supported on the driven shaft, mixing and mulling mechanisms in the lower unit supported on the driven shaft, means for circulating air upwardly through the superimposed units as the mechanisms in the respective units treat the materials including apertu-red portions in said units'and a blower having an outlet near the bottom of saidlower unit for delivering cool air to the material therein to cool the same before passing upwardly through said apertured portions into the intermediate and top units, and means for heating the interior of the intermediate unit to dry clean the material therein by scouring and oxidation and permitting the heated air to be utilized in the upper unit for preheating the material being treated therein.

5. A spent material reclaiming apparatus coml4 prising a housing including a plurality of super imposed communicating chambers, means for batch feeding material in manually timed order through the respective chambers, rabble mechanisms in a plurality of said chambers, mixing and mulling mechanisms in another of said chambers, a driven shaft projecting through the housing and through the respective chambers and supporting the rabble, mixing and mulling mechanisms in said chambers to drive the same, means for operating the driven shaft, means for cooling the driven shaft and for circulating air currents through the communicating chambers, including iapertured portions between said chambers and a blower for discharging cool air into the lowest of said chambers to cool the same by forcing air therethrough, before allowing the air to pass up through the upper chambers, means for dry cleaning the material in one of said chambers and preheating the material in another of 'said chambers before entering the dry cleaning chamber, and means connected with two of said chambers for withdrawing the dust and fines from the material while the material is being preheated in one chamber and while the material is being cooled by the air currents and dry cleaned in another of said chambers.

6. In a spent material reclaiming apparatus of the class described, a housing including a plurality' of superimposed communicating chambers, meansfor batch feeding the material to said chambers in manually timed order, material treating mechanisms in each of the chambers, a Y

driven shaft projecting through all of said chambers and supporting the treating mechanisms, means for circulating air through the connected chambers for cooling the driven shaft and for aerating the material batches being treated in the respective chambers including portions having communicating apertures between each adjacent chamber and a blower disposed for forcing air into the lowest of said chambers and through the material therein to cool thesame before directing the air upwardly through said communicating chambers, means for operating the driven shaft, 'a collector positioned to receive air and fines discharged from the uppermost of said chambers and from the driven shaft, a second collector connected with the lowermost of said chambers for withdrawing fines therefrom, and a heating means connected with still another of said chambers for removing the bonding and foreign matter coatings from the material grains to dry clean the same.

7. An apparatus for reclaiming spent foundry sand, which includes a first unit, means for delivering a batch of spent foundry sand to said unit, a rabble mechanism in said first unit, a dischargemechanism in said first unit operable for permitting a discharge of the batch after being treated in the first unit, and a second unit positioned beneath the first unit, a combination to produce oxidation to remove rabble and air supply mechanism in said second unit for treating a batch of the foundry sand received from the first unit and for supplying air thereto, a burner mechanism connected with the second unit for subjecting the sand while being rabbled and'aerated tova temperature suflicient the bonding and carbonaceous coatings from the sand grains to produce a clean, hot, dry sand, a third unit engaged beneath the second unit, scraping, plowing and mulling mechanisms in the third unit, a discharge door mechanism in the second unit for discharging a batch of. the sand from the second REFERENCES crmn The following references are of record in the file of this patent:

amass Number UNITED STATES PATENTS I Name Date Fisher Sept. 1, 1925 Kelley Mar. 19, 1925 Fisher May 21, 1929 Nichols May 15, 1945 Lewers June 8, 1937 Hartley June 4, 1930 Simpson Apr, 20, 1920 Dvorak Mar. 23, 1943 Beardsley Jan. 19, 1943 

